On_off_config, Vin_on, Vin_off – Maxim Integrated MAX15303 PMBus Command Set User Manual

Page 7

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MAX15303 PMBus Command Set User’s Guide

Page 7 of 52

ON_OFF_CONFIG

Reference:

Standard Command

Lockable:

Yes

Command Code:

0x02

Format:

Bit field

Data Bytes:

1

Units:

N/A

Transfer:

Read/Write Byte

Factory Value:

0x16 (see Description table)

Description/Notes: See Section 12.2 of the PMBus Specification Part II.

Useful Values for the ON_OFF_CONFIG command:
0x00

Output always enabled (note: same as 0x01-0x0F)

0x10

Output always disabled (note: same as 0x11-0x13)

0x14

Ignore bit 7 of

OPERATION

, require EN low to run, soft-off on loss of EN

0x15

Ignore bit 7 of OPERATION, require EN low to run, immediate-off on loss of EN

0x16

Ignore bit 7 of OPERATION, require EN high to run, soft-off on loss of EN (factory setting)

0x17

Ignore bit 7 of OPERATION, require EN high to run, immediate-off on loss of EN

0x18

Require bit 7 of OPERATION to run, ignore EN (note: same as 0x19-0x1B)

0x1C

Require bit 7 of OPERATION and EN low to run, soft-off on loss of EN

0x1D

Require bit 7 of OPERATION and EN low to run, immediate-off on loss of EN

0x1E

Require bit 7 of OPERATION and EN high to run, soft-off on loss of EN

0x1F

Require bit 7 of OPERATION and EN high to run, immediate-off on loss of EN

In general, odd values of ON_OFF_CONFIG that require a valid EN signal will have an immediate-off
shutdown when EN is not valid. Even values that require EN will have a soft-off shutdown when EN is
not valid.

After writing the ON_OFF_CONFIG command to enable the output, the PMBus master must either
wait for a time equal to (TON_DELAY + TON_RISE + 50ms), or wait for PG to assert, before sending
additional PMBus commands.

VIN_ON

Reference:

Standard Command

Lockable:

Yes

Command Code:

0x35

Format:

Linear

Data Bytes:

2

Units:

V

Transfer:

Read/Write Word

Factory Value:

0xCB00 (6.0V)

Description/Notes: See Section 14.5 of the PMBus Specification Part II.

The MAX15303 hardware has 8-bit resolution for the minimum input voltage required for regulation,
to a maximum value of ≈14.75V.

The desired value of VIN_ON is retained in memory, regardless limitations imposed by the 8-bit fault
limit resolution, but the read-back value is based on actual hardware register settings.

VIN_OFF

Reference:

Standard Command

Lockable:

Yes

Command Code:

0x36

Format:

Linear

Data Bytes:

2

Units:

V

Transfer:

Read/Write Word

Factory Value:

0xCAC0 (5.5V)

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